Spark plug cover



` M. s. HOOK 2,446,007

SPARK PLUG COVER July 27, 194s.

Filed Dec. 11,- 1944 ,34 J /5 /7 el zz ATTO RN EVS.

` Patented July 27, Y194s SPARK rLUG covER `Melvin S. Hook; Gurnee, ,111., 'assignor to 'Outlboard, Marine &. Manufacturing Company, A 'Waukegan Ill., a corporation of Delaware Application December 11, 1944,-SerialNo. 567,686 y' This invention relatestoimproxements in sp'ark plug covers.

It is a primary object of the invention to provide va novel, simple and inexpensive sparkplug cover of `compact form and' unusual effectiveness in completely excluding nic'iis'ture from the electrical l realms. (c1. 114-77) connection to the plug and from the joint between the plug electrode and the porcelain.

It is a further object Vof the inventionto'provide a-spark plug cover of 'such size, locationand con I struction as to minimizeheat deterioration-and' consequent leakage by :spacing the jsparkplug Y cover as f ar as possiblej-from thejmetal-b 'the spark plug.

Other objects of the following disclosure'. 'In thel drawings t.'

Fig.v- 1 is a'side elevation-veia v'spark'-Jplilgtoi Vwhich is applied a 'spark vplug -cover embodying the invention.

, Fig. 2 is a side elevation -ofthepartslshewnfinj, Fig.1.' Uw Y Fig. 3 ifs Van enlarged Aview taken inf-vif'ertical-V` section through' the sparkfplug cover.

Fig. 4 is an enlarged view'taken in horizontal section through the spark plug' cover. I

Fgp is a view in rperspective showingr details v. Y ofthe contact clipand leadterminal separately. L Like parts are identified by the same reference.

characters throughout. the" several views.-

l linvlenizitfin` will to those'skilled in lthearteupon analysis of" Athey j. f f i V`I5 ofthe spark plug cover tobe handled unitarily Y. 2 the clip extend through clearly .shown in Figs. 3 and 4. The head portion 26 ofthe clip remains in the base of the bore V into which thelead is inserted, the head beingA n -in electrical contact withthe fanned out ends 2 3V of the lead wires.

lExtending transversely throughthe body pory tion I5 ofthe spark plug cover is a bore 30 inter- ,use of sected by aperture 29 and accommodating a nut v3| which has, at the level of aperture 29,1an

annular groove 32 engaged by thelegs 21, 23.0f

vthe spring clip 25. The spring clip not only affords an electrical connection between the lead f and theterminal coupling nut 3l, but also serves to lock the terminal nut within the body portion V ltherewith.` The interlocking engagement be- 1 tween the clip legs 21, 28 and the groove `32 of"- the terminal nut precludes the terminal nut from .A fgmaterial axial displacement in either direction Ylongitudinally of borein vwhich it rotates.

f Conventionally, as spark'plug inclu'desjametal base at 6' carrying the grounded electrodevfl.v

Insulated by the porcelain'sfrom .the metal vbase .is the center electrode-Il provided. at its upper endV with la threaded terminalIIlon which anut I I engages the porcelain.

, My iniproved spark plug cover comprises'afbody portion I5 which, in .this embodiment; is: of ,gen-

erally cylindrical f orm. One of its endsis inte-: riorly socketed and threadedl at I6 torec'eivethe gland nut l'kfllrrder pressure of the gland nut,l .transmitted through` washer I8, the resilient. di-

eleetricgasket I9 isf deformed and caused topressv s inwardly at 20 upon the' insulating coverof rubber or the like at 2I whichvencloses the bundle of wires 422 comprising the ,igntionlead It isdef Vsirable that the lead should no t be fabric covered.'

l asthe' fabric would'carry -moisture through the 1 sealing gasket I9. f

At the end of the insulation 2|,v`the wires are tanned out at 23 as best shown in Fig. 5 to engage a spring clip 25, the intermediate portion of which is formedat 26 to constitute'l ahead from which the legs 21 and 28 diverge. The leg portions of body I5, glandl I1, spring clip 25. and the terminal -.coup1ing nut 3I, 34 constitute a unit which'mayz'* be sold and-handled either withorrwithout, the'v gaskets I9, 35 and '33. Although vthe terminal nut v assembly cannot 'escape 'from the. b ore .3 II,A it l a is freely rotatable therein. In the courseof terr' minal nut .rotation 'for screwing it on to or rem'ov4 ing it from the terminal I0, the entire spark Yplug i' cover is applied to or-removed from 'the sparkA ,f

j The terminal nut is a metallic insert preferably provided at 3 3vwith knurling about which a di velectric handle 34 ismolded. The lower surface =of thehandle34 ,constitutes a. 'shoulder-at- 35E r which engages a gasket 36, preferably of synthetic rubber,{which is clampedin'the bottom of- -cjon ter .bore'31 to seal 'hermeticallythe joint btstw'eenI `An4 opposite .downwardly opening'counter. bore-f t' at 38fundercut at 38' V receives and retains another gasket 39within'whichthejrng.nutj II of the? fsparklplug isreceivabl'e. "gasket Yseatsv on 'the extreme end of the porcelain :B'of the. plug, and bears against thefring nut'I Land .the portions of body I5 whichlieat" theendandsidefof'the-. counterv bore 38 to. hermetically vseal 'the-.joint between these parts.

The mechanical retention of the terminal nut l `by the 'clip 25 is merely toV prevent Aloss offthe' flut-'- during handling. In use, the 'wiresyhave-n-H '-f mechanical load. The tightening of the'nutseats both gaskets 36 and 39. It will be ,apparent from the'foregoing that "the plus.

the aperture" 29V ofthe l v insulating body and are spread against escape as y. A

. rubber or synthetic rubber.

to engage the fanned out wires at 23 forcibly with the head 26 of the spring clip 25. Thereupon the gland is tightened to resist any normal tension tending to pull the lead from the cover.

The space enclosed within the three seals provided by the gaskets i9, 38 and 39 is desirably small in its capacity to prevent breathing." The three gaskets completelyv prevent moisture from creeping into the interior of the device from above or below or along the lead. Since the entire spark plug cover and lead are supported at the extreme end o f the spark plug, the device makes maximum use of the dielectric capacity and low heat transmission capacity o1' the spark plug porcelain 8. A

The terminal nut insert 3l andthe spring clip 2l are made of brass or other electrically conductive material.- The bodyv portion Hi, the terminal nut handle 34 and the gaskets I9, 36 and 30 are preferably dielectric and the several gaskets are preferably elastically deformable The gland nut I1 and its washer I8 may be either metallicl or nonmetallic.

In practice, my improved spark plug cover will completely exclude moisture from the electrode terminal oi the spark plug even though the spark plug and cover are submerged in water. The spark'plug cover as herein disclosed is not only desirable on outboard motors and marine engines, but is of general application to internal combustion engines for automotive and aviation and industrial purposes. The possibility of leakage and arcing between the high tension conductors and ground due to salt, moisture, dust or other foreign matter on the spark plug porcelain is eliminated.

With all of its advantages, the spark plug cover is nevertheless simple in design and economical of manufacture.

I claim:

1. A spark plug cover for housing an electrical connection from an insulated high tension lead to a spark plug and comprising a dielectric body having a nrst bore extending through said body and a second bore opening into said body and communicating with said irst bore, said body being provided with counter bores about the second bore and both ends of the first bore, an- I nular gaskets in the respective counter bores, a terminal nut rotatable in therst bore and provided with a shoulder engaging its associatedin, said body having a shoulder in `said second bore against which said gasket seats, and a gland nutthreaded in said body in the counter bore of said second bore for applying pressure to said third gasket, high tension lead wires having end portions embedded in impermeable insulation and extending through said gasket, with the ends 4 f of the wires exposed and tanned out vin pressure relation to the head of said contact clip. 2. A spark plug cover having a body portion impervious to moisture and lead wires scaled in one end of the body, a bore extending through the bodytransversely of the lead 'wires with its ends counterbored to provide spaced annu-lar shoulders on opposite sides of the axis along which the leadwires enter, compressible annular gaskets seated against said shoulders, a coupling nut rotatable in said .bore and having an electrically conductive portion in position for threaded engagement with the upper' end of the central terminal of the spark plug, said nut having a dielectric cap portion tted to one of the counterbores and adapted to apply clamping pressureto said gaskets, one of said gaskets being adapted for sealing engagement with the body at the inner end of its associated counterbore and the other of said gaskets being adapted for sealing engagement with the porcelain end Aof a' spark plug when the central terminal 'of such and an electrically conductive clip having a forked end in pressure contact with the conductive portion o i said .nut and having a head portion with which said lead wires are engaged.

3. In a spark plug cover, the combination with an apertured body portion impervious to moisture and covering the ends of high tension lead wires in sealing relation thereto, a sealing gasket at one end of the body aperture adapted to bear on the porcelain head of an ordinary spark plug, a coupling nut seated in the body aperture and said nut having a dielectric exposed portion and an electrically conductive inner portion of less diameter encircled by a compressible sealing gasket between the dielectric portion and the body, and a forked connecting clip having a head portion in electrical contact with the lead wires and its fork arms in electrical contact with the conductive portion of the nut, said nut having a socket in which the terminalv of an ordinary spark plug may have threaded engagement, whereby rotation of the nutin one direction may apply sealing pressure to both of said gaskets while moving into threaded engagement with said terminal.

4. A cover applicable to a conventional spark plug having a porcelain insulator and projecting terminal screw for providing a sealed high tension connection to said screw, said'cover comprising a body having first and second bores intersecting at right angles, the rst bore having counterbores at both ends and the second bore having a counterbpre opening-to one side of said body, rst and second compressible moisture-resistant annular gaskets seated in the respective counterbores of the rst bore, the first said gasket being formed to engage -a spark plug insulator adjacent its upper end with the terminal screw of the spark plug extending into said rst, bore, a nut having an electrically conductive portionffrotatably mounted in said first bore `and.@dielectric head portion forming a shoulder engageable with the second of said gaskets, said head portion projecting from said bodyfor manipulation of said nut, a third gasket of deformable material in the counterbore of the second bore, and a packing gland threaded `to said body in said last mentioned counterbore for compressing said third gasket upon an insulated high tension lead in said last mentioned counterbore, said second bore opening into the rst bore at the level of the electrically conductive portion of said nut where by to provide access for electrical -connection to said conductive nut portion and thereby to the spark plug terminal from such a lead.

5. A device applicableto the end of a high tension lead for unitary handling therewith and for i body having a terminal-receiving bore opening through the body and provided at both ends with a counterbore, together with a high tension bore opening laterally from the first mentioned bore and also provided witha' counterbore, a nut having an electrically conductive portion adapted for threaded engagement with the spark plug terminal and rotatably tted in said terminalreceiving bore, said nut having a dielectric head of larger diameter than its conductive portion and disposed in one of the counterbores of the terminal-receiving bore, the other counterbore of the terminal-receiving bore being provided with sealing means formed for engagement with the upper end of a. spark plug insulator. an electrical conductor extending through the high tension bore into the terminal-receiving bore of said body and mechanically interlocked with the electrically conductive portion of said nut, said last mentioned nut portion being provided with an opening in which said conductor is engaged, whereby said nut is keyed in said term-inal-receiving bore, together with means comprising a deformable gasket, and a packing gland in threaded connection with said body in the counterbore of said high tension bore for holding iny said last mentioned bore an insulated high tension lead in engagement with said conductor, the aforesaid nut constituting means for simultaneously holding said body at the end of a spark plug while effecting sealed electrical connection within said body to the spark plug terminal.

6. The combination set forth in claim in which said conductor comprises a bifurcated member and the opening in the electrically conductive portion of said nut constitutes an annular groove .in which the bifurcated ends of said conductor are divergently engaged to key said nut to said body against axial withdrawal therefrom while 5 permitting rotation of said nut respecting said body for engagement with and disengagement from a spark plug terminal.

7. As a new article of manufacture, a conductor adapted for use in a spark plug cover to effect lo electrical high tension connection to a spark plug nut while keying said nut within said cover, said vmember comprising a pair oilegs mutually spaced REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date i 1,050,885 Welch Jan. 21, 1913 1,139,973 Herz M'ay 18, 1915 1,167,820 Herz 1---- Jan. 11, 1916 1,191,162 Dixon July 18, 1916 1,298,799 Schmidt Apr. 1, 1919 1,595,031 Steiner Aug. 3, 1926 1,862,876 Wright et al. Jilne 14, 1932 1,912,980 Hoogendorn June 6, 1933 2,177,509 l Abbott Oct. 24, 1939 FOREIGN PATENTS 40 Number Country Date 25,802/1905 Great Britain Oct. 18, 1906 155,066 Great Britain 1920 290,820 Great Britain May 24, 1928 f 746,326 France Mar. 7, 1933 

